US8045097B2 - Liquid crystal display device and viewing angle control module - Google Patents

Liquid crystal display device and viewing angle control module Download PDF

Info

Publication number
US8045097B2
US8045097B2 US12/297,922 US29792207A US8045097B2 US 8045097 B2 US8045097 B2 US 8045097B2 US 29792207 A US29792207 A US 29792207A US 8045097 B2 US8045097 B2 US 8045097B2
Authority
US
United States
Prior art keywords
liquid crystal
viewing
angle
display device
crystal panel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US12/297,922
Other versions
US20090174843A1 (en
Inventor
Takehiko Sakai
Tsuyoshi Okazaki
Katsuhiko Morishita
Yoshiharu Kataoka
Chikanori Tsukamura
Dai Chiba
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Assigned to SHARP KABUSHIKI KAISHA reassignment SHARP KABUSHIKI KAISHA ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TSUKAMURA, CHIKANORI, KATAOKA, YOSHIHARU, MORISHITA, KATSUHIKO, CHIBA, DAI, OKAZAKI, TSUYOSHI, SAKAI, TAKEHIKO
Publication of US20090174843A1 publication Critical patent/US20090174843A1/en
Application granted granted Critical
Publication of US8045097B2 publication Critical patent/US8045097B2/en
Expired - Fee Related legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
    • G02F1/13471—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/1323—Arrangements for providing a switchable viewing angle
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133638—Waveplates, i.e. plates with a retardation value of lambda/n
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/08—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with a particular optical axis orientation

Definitions

  • the present invention relates to a display device (e.g., a liquid crystal display device) capable of switching viewing angle characteristics.
  • a display device e.g., a liquid crystal display device
  • a display device In general, a display device is required to have a viewing angle characteristic (wide viewing angle characteristic) that allows a sharp image to be viewed from a larger number of viewing points.
  • a viewing angle characteristic wide viewing angle characteristic
  • PDA Personal Data Assistant
  • the display device takes a viewing angle characteristic (a narrow viewing angle characteristic) with which only a user can view a displayed image (from a limited viewing point) and the surrounding people cannot view the displayed image (from other viewing points).
  • one display device is provided with capability of switching between a wide viewing angle characteristic and a narrow viewing angle characteristic.
  • Patent Document 1 discloses a liquid crystal display device in which: a viewing-angle-control liquid crystal panel is provided above a display liquid crystal panel; the viewing-angle-control liquid crystal panel and the display liquid crystal panel are sandwiched by two polarizing plates; and a viewing angle characteristic is controlled by adjusting a voltage that is applied to the viewing-angle-control liquid crystal panel, so that a viewing angle characteristic is controlled.
  • a viewing-angle-control liquid crystal panel and an upper polarizing plate need to be provided in accordance with a rubbing direction of a substrate constituting a display liquid crystal panel (or a direction of a polarization axis of a lower polarizing plate).
  • the display liquid crystal panel determines a direction in which an image can be viewed and a direction in which an image cannot be viewed (viewing restricted direction) in the case of a narrow viewing angle characteristic operation. Therefore, the viewing restricted direction cannot be set unrestrainedly.
  • An object of the present invention is to provide a liquid crystal display device that allows a viewing restricted direction to be set as appropriate.
  • the liquid crystal display device of the present invention that includes a display liquid crystal panel and a viewing-angle-control liquid crystal panel and that is capable of switching viewing angle characteristics
  • the liquid crystal display device includes: a retardation member for setting a viewing restricted direction which retardation member being provided between the display liquid crystal panel and the viewing-angle-control liquid crystal panel.
  • an appropriate retardation member for example, a 1 ⁇ 2 wavelength plate
  • a polarization direction a direction of a polarization axis
  • the liquid crystal display device may have an arrangement in which: the display liquid crystal panel includes a first polarizing member, a display liquid crystal cell, and a second polarizing member overlapped in this order, and the viewing-angle-control liquid crystal panel includes a third polarizing member, a viewing-angle-control liquid crystal cell, and a fourth polarizing member overlapped in this order; and the retardation member is provided between the second polarizing member and the third polarizing member.
  • the retardation member may be a half wavelength plate (1 ⁇ 2 ⁇ plate).
  • the second and third polarizing members are provided so that an angle between a transmission axis of the second polarizing plate and an axis of the half wavelength plate becomes equal to an angle between the axis of the half wavelength plate and a transmission axis of the third polarizing plate.
  • a polarization direction (a direction of a polarization axis) of a linearly polarized light that has passed through the display liquid crystal panel can be changed while an intensity of the linearly polarized light is kept the same.
  • the retardation member may be arranged by two 1 ⁇ 4 wavelength plates provided in parallel (so that axes of the 1 ⁇ 4 wavelength plate become parallel to each other).
  • the liquid crystal display device may further include: a retardation plate at least either between the first polarizing member and the display liquid crystal cell or between the second polarizing member and the display liquid crystal cell. Moreover, the liquid crystal display device may further include: a retardation plate at least either between the third polarizing member and the viewing-angle-control liquid crystal cell or between the fourth polarizing member and the viewing-angle-control liquid crystal cell. In this way, the retardation plate is provided between a polarizing plate and a liquid crystal cell. This makes it possible to perform optical compensation of an elliptically polarized light. This elliptically polarized light is produced by birefringence that is caused by the liquid crystal cell.
  • the liquid crystal display device may be provided with a backlight and the display liquid crystal panel provided between the backlight and the viewing-angle-control liquid crystal panel. Moreover, the liquid crystal display device may be provided with a backlight and the viewing-angle-control liquid crystal panel provided between the backlight and the display liquid crystal panel.
  • the light emitted from a backlight has directivity.
  • a viewing angle control module of the present invention constituting a liquid crystal display device capable of switching, in combination with a display liquid crystal panel, viewing angle characteristics
  • the viewing angle control module includes: a retardation member for setting a viewing restricted direction and a viewing-angle-control liquid crystal panel which are provided in this order from a side provided with the display liquid crystal panel.
  • the arrangement makes it possible to change, by use of the retardation member, a polarization direction (a direction of a polarization axis) of the linearly polarized light that has passed through the display liquid crystal panel or the viewing-angle-control liquid crystal panel.
  • a viewing restricted direction set by the viewing-angle-control liquid crystal panel can be changed. That is, by using an appropriate retardation member and setting an axis of the retardation member appropriately, a viewing restricted direction can be set as appropriate.
  • the viewing-angle-control liquid crystal panel may include a first polarizing member, a viewing-angle-control liquid crystal cell, and a second polarizing member overlapped in this order.
  • the retardation member may be a half wavelength plate.
  • an angle between a polarization axis of light that enters the viewing angle control module or exits from the viewing angle control module and an axis of the half wavelength plate is arranged to be equal to an angle between the axis of the half wavelength plate and a transmission axis of the first polarizing plate.
  • a polarization direction (a direction of a polarization axis) of a linearly polarized light that has passed through the display liquid crystal panel can be changed while an intensity of the linearly polarized light is kept the same.
  • the retardation member may be arranged by two 1 ⁇ 4 wavelength plates provided in parallel.
  • an appropriate retardation member for example, a 1 ⁇ 2 wavelength plate
  • a polarization direction a direction of a polarization axis
  • a viewing restricted direction can be set as appropriate in the case of a narrow viewing angle characteristic operation.
  • FIG. 1 is an exploded perspective view illustrating an example of an arrangement of a liquid crystal display device of the present invention.
  • FIG. 2 is an exploded perspective view illustrating an example of an arrangement of the liquid crystal display device of the present invention.
  • FIG. 3 is a cross sectional view illustrating an arrangement an arrangement of the liquid crystal display device of the present invention.
  • FIG. 4 is a diagram schematically illustrating an effect of a ⁇ /2 plate.
  • FIG. 5 is a diagram schematically illustrating an effect of a setting retardation plate.
  • FIG. 6 is a diagram schematically illustrating an effect of a setting retardation plate.
  • FIG. 7 is a cross sectional view illustrating another arrangement of the liquid crystal display device of the present invention.
  • FIG. 8 is a cross sectional view illustrating a modified example of the liquid crystal display device of the present invention.
  • FIG. 9 is a cross sectional view illustrating an arrangement in which a display liquid crystal plate is combined with a viewing-angle-control liquid crystal panel to which a setting retardation plate has been fixed.
  • FIG. 10 is a cross sectional view illustrating an arrangement in which a viewing-angle-control liquid crystal plate is combined with a display liquid crystal panel to which a setting retardation plate has been fixed.
  • FIG. 11 is a cross sectional view illustrating an example of an arrangement of the viewing-angle-control liquid crystal panel in the liquid crystal device of the present invention.
  • FIG. 12( a ) is a perspective view illustrating an alignment state of a liquid crystal molecule of the viewing-angle-control panel in a narrow viewing angle mode.
  • FIG. 12( b ) is a perspective view illustrating an alignment state of a liquid crystal molecule of the viewing-angle-control panel in a wide viewing angle mode.
  • FIG. 13 is a diagram that expresses, in two angles (a polar angle and an azimuth angle), a plurality of viewing points with respect to the viewing-angle-control panel provided in the same direction as the viewing-angle-control panel in each of FIGS. 12( a ) and 12 ( b ), and schematically explains each of the plurality of viewing points.
  • FIG. 14( a ) is a diagram illustrating a positional relationship between a liquid crystal molecule and a transmission axis of a polarizing plate in a case where the viewing-angle-control panel is viewed from a viewing point P 1 .
  • FIG. 14( b ) is a diagram illustrating a positional relationship between the liquid crystal molecule and the transmission axis of the polarizing plate in a case where the viewing-angle-control panel is viewed from a viewing point P 2 .
  • FIG. 14( c ) is a diagram illustrating a positional relationship between the liquid crystal molecule and the transmission axis of the polarizing plate at the time when the viewing-angle-control panel are viewed from a viewing point P 3 .
  • FIG. 15 is a chart illustrating a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the narrow viewing angle mode.
  • FIG. 16 is a chart illustrating a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the wide viewing angle mode.
  • FIG. 17 is a cross sectional view illustrating an arrangement in which (i) one ⁇ /4 plate is fixed on an upper surface of the display liquid crystal panel and another ⁇ /4 plate is fixed on a lower surface of the viewing-angle-control liquid crystal panel and (ii) the display liquid crystal panel with the one ⁇ /4 plate is combined with the viewing-angle-control liquid crystal panel with the another ⁇ /4 plate.
  • FIG. 3 is a cross sectional view schematically illustrating a liquid crystal display device 10 of the present invention.
  • the liquid crystal display device 10 includes a display liquid crystal panel 1 that displays an image, a viewing-angle-control liquid crystal panel 2 that switches viewing angle characteristics of the liquid crystal display device 10 , a setting retardation plate (1 ⁇ 2 ⁇ plate) 7 that is provided between the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2 for setting a viewing restricted direction, and a backlight 3 .
  • a first polarizing plate 13 In the display liquid crystal panel 1 , a first polarizing plate 13 , a display liquid crystal cell 11 in which a liquid crystal is sandwiched by a pair of light-transmitting substrates, and a second polarizing plate 12 are provided in this order.
  • a third polarizing plate 23 In the viewing-angle-control liquid crystal panel 2 , a third polarizing plate 23 , a viewing-angle-control liquid crystal cell 21 in which a liquid crystal is sandwiched by a pair of light-transmitting substrates are provided in this order.
  • the setting retardation plate 7 is provided between the second polarizing plate 12 and the third polarizing plate 23 .
  • the liquid crystal display device 10 can take a wide viewing angle mode (wide viewing angle characteristic) and a narrow viewing angle mode (narrow viewing angle characteristic), by a switching operation of the liquid crystal provided in the viewing-angle-control liquid crystal cell 21 .
  • a wide viewing angle mode an image of the display liquid crystal panel 1 can be viewed from a larger number of viewing points.
  • the narrow viewing angle mode the image of the display liquid crystal panel can be viewed from only a limited viewing point.
  • the narrow viewing angle mode is suitable in a case where it is unfavorable that the image of the display liquid crystal panel 1 is viewed by others.
  • the wide viewing angle mode is suitable, for example, in general use or in a case where an image of the display liquid crystal panel 1 is desired to be viewed simultaneously by a plurality of people.
  • a liquid crystal mode, a cell structure, and a driving mode of the display liquid crystal panel 1 may be determined as appropriate. That is, any liquid crystal panel (for example, a TN liquid crystal panel or an ASV liquid crystal panel) capable of displaying a character, an image, or a moving image may be used as the display liquid crystal panel 1 .
  • the display liquid crystal panel 1 may also be a semi-transmissive liquid crystal panel. Further, the display liquid crystal panel 1 may be a panel capable of performing color display or a panel exclusive to monochrome display.
  • An arrangement of the backlight 3 is also determined as appropriate. For example, the backlight 3 may be a backlight that emits light having directivity.
  • a liquid crystal layer of the viewing-angle-control liquid crystal cell 21 is made of, for example, a positive nematic liquid crystal in a homogenous alignment.
  • a surface of the second polarizing plate 12 may be subjected to a diffusion treatment such as an AG treatment.
  • the first polarizing plate 13 is a so-called a clear polarizing plate that is not subjected to a surface treatment.
  • FIGS. 12( a ) and 12 ( b ) are diagrams each schematically illustrating mainly an arrangement of the viewing-angle-control liquid crystal panel 2 .
  • FIG. 12( a ) shows an alignment state of a liquid crystal molecule of the viewing-angle-control panel in the narrow viewing angle mode.
  • FIG. 12( b ) shows an alignment state of a liquid crystal molecule of the viewing-angle-control panel in the wide viewing angle mode.
  • the viewing-angle-control liquid crystal cell 21 includes a pair of light-transmitting substrates 21 a and 21 b .
  • transparent electrodes are formed by use of, for example, ITO (Indium Tin Oxide), respectively.
  • ITO Indium Tin Oxide
  • the display liquid crystal cell 11 needs to drive a liquid crystal for each display unit such as a pixel unit or a segment unit, the display liquid crystal cell 11 has an electrode structure in accordance with the display unit.
  • an electrode arrangement of the viewing-angle-control liquid crystal cell 21 is not limited.
  • the viewing-angle-control liquid crystal cell 21 may have, for example, an arrangement in which uniform electrodes are formed on an entire surface of each of the light-transmitting substrates 21 a and 21 b for carrying out uniform switching all over a display surface or other appropriate electrode arrangement.
  • an alignment film (not illustrated) is formed on an upper layer of the transparent electrode.
  • This alignment film aligns liquid crystal molecules 21 c .
  • the alignment film is subjected to a rubbing treatment according to a publicly known method.
  • Arrows Ra and Rb in FIGS. 12( a ) and 12 ( b ) shows rubbing directions of the light-transmitting substrates 21 a and 21 b , respectively.
  • the rubbing direction Ra with respect to the alignment film of the light-transmitting substrate 21 a is substantially parallel and in a reverse direction with respect to the rubbing direction Rb with respect to the alignment film of the light-transmitting substrate 21 b.
  • the viewing-angle-control liquid crystal device 21 (hereinafter, referred to as a liquid crystal cell 21 as appropriate) is a so-called parallel cell that has a twist angle of 0 (no twist).
  • the liquid crystal provided in the liquid crystal cell 21 is a liquid crystal in a homogenous alignment. Accordingly, each of the liquid crystal molecules 21 c of the liquid crystal cell 21 is aligned so that a long molecular axis becomes parallel to a substrate surface of each of the substrates 21 a and 21 b at the time when no voltage is applied.
  • a retardation value d ⁇ n (d is a thickness of the cell, and ⁇ n is a birefringence) of the liquid crystal layer of the liquid crystal cell 21 is, for example, in a range of 350 nm to 450 nm.
  • the liquid crystal molecules 21 c When a voltage is applied between electrodes (not illustrated) that are provided on the light-transmitting substrates 21 a and 21 b , respectively, the liquid crystal molecules 21 c gradually changes a direction according to a size of the applied voltage.
  • the liquid crystal molecule 21 c changes the direction from a state parallel to the substrate surface, within a plane that is perpendicular to a normal of each of the light-transmitting substrates 21 a and 21 b as illustrated in FIG. 12( a ) and parallel to the respective rubbing directions Ra and Rb with respect to the alignment films of the light-transmitting substrates 21 a and 21 b .
  • FIG. 12( a ) shows a state in which the long molecular axis of the liquid crystal molecule 21 c is slightly tilted with respect to the normal of each of the light-transmitting substrate 21 a and 21 b due to an applied voltage V L (a voltage in a range of, for example, approximately 2.5 V to 3.5 V).
  • V L a voltage in a range of, for example, approximately 2.5 V to 3.5 V.
  • V H a voltage, for example, not less than 5.0 V
  • the third polarizing plate 23 provided below the liquid crystal cell 21 and the fourth polarizing plate 22 provided above the liquid crystal cell 21 are provided so that a transmission axis X 23 of the polarizing plate 22 and a transmission axis X 22 of the polarizing plate 23 become substantially orthogonal.
  • the transmission axis X 23 and the transmission axis X 22 are arranged to be substantially orthogonal in this way (that is, an angle between the transmission axis X 22 and the transmission axis X 23 is in a range of 800 to 100°), a sufficient effect can be obtained from switching viewing angles.
  • the transmission axis X 22 of the fourth polarizing plate 22 keeps tilt at an angle in a range of 40° to 50° (preferably 45°).
  • a viewing point with respect to the viewing-angle-control panel 2 is expressed in an azimuth angle ⁇ and a polar angle ⁇ that use a center of the fourth polarizing plate 22 as a reference.
  • the azimuth angle ⁇ is a rotational angle of a line connecting between a center 22 c of the fourth polarizing plate 22 a and a point at which a perpendicular line from a viewing point to a plane including a surface of the fourth polarizing plate 22 intersects with the plane.
  • the polar angle ⁇ is an angle between a line connecting the center 22 c of the fourth polarizing plate 22 with the viewing point and a normal of the fourth polarizing plate 22 .
  • FIG. 13 shows three viewing points P 1 through P 3 with respect to the viewing-angle-control panel 2 that is provided in the same direction as that in FIGS. 12( a ) and 12 ( b ).
  • the azimuth angle ⁇ increases clockwise in a case where the viewing-angle-control panel 2 is viewed from an upper side in a normal direction of the fourth polarizing plate 22 , on an assumption that the azimuth angle of the viewing point P 1 is 0°.
  • FIGS. 14( a ) through 14 ( c ) the following explains display states that are observed from the viewing points P 1 through P 3 shown in FIG. 13 , respectively, in a case where the long molecular axis of the liquid crystal molecule 21 c is tilted, due to the applied voltage V L that is applied to the liquid crystal cell 21 , at a slight angle with respect to the normal of each of the light-transmitting substrates 21 a and 21 b (in the case of FIG. 12( a )).
  • FIG. 15 is a chart illustrating a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the narrow viewing angle mode.
  • FIG. 16 is a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the wide viewing angle mode.
  • the liquid crystal molecule 21 c is, as illustrated in FIG. 14( a ), in a state in which the long molecular axis of the liquid crystal molecule 21 c is in parallel to a viewing point direction (a direction from the viewing point to the molecule). Consequently, a linearly polarized light that passes through the third polarizing plate 23 and enters the liquid crystal cell 21 toward the viewing point P 1 is not given birefringence by the liquid crystal molecule 21 c . As a result, the fourth polarizing plate 22 shields the linearly polarized light.
  • a display viewed from the viewing point P 1 becomes a black display.
  • the applied voltage V L that is applied to the liquid crystal cell 21 is in a range of approximately 2.5 V to 3.5 V
  • L 1 through L 8 in FIG. 15 are equipotential lines that show distribution of viewing angles that have luminances of 50 cd/m 2 , 100 cd/m 2 , 150 cd/m 2 , 200 cd/m 2 , 250 cd/m 2 , 300 cd/m 2 , 350 cd/m 2 , and 400 cd/m 2 , respectively.
  • the liquid crystal molecule 21 c is, as illustrated in FIG. 14( b ), in a state in which the long molecular axis of the liquid crystal molecule 21 c is slightly tilted with respect to each of the transmission axis X 22 of the third polarizing plate 22 and the transmission axis X 23 of the third polarizing plate 23 . Consequently, a very slight birefringence is produced by the liquid crystal molecule 21 c in a linearly polarized light that passes through the third polarizing plate 23 and enters the liquid crystal cell 21 toward the viewing point P 2 .
  • the fourth polarizing plate 22 shields the linearly polarized light. Accordingly, a display viewed from the viewing point P 2 also becomes a black display. Moreover, a display viewed from a position opposed to the viewing point P 2 , that is, a display in a case where the azimuth angle ⁇ is 270°, also becomes a black display, because of the same principle as in the observation from the viewing point P 2 .
  • the applied voltage V L that is applied to the liquid crystal cell 21 is in a range of approximately 2.5 V to 3.5 V, a sufficient light-shielding state for preventing others from peeking at the display is obtained, as illustrated in FIG.
  • the liquid crystal molecule 21 c is, as illustrated in FIG. 14( c ), in a state in which the long molecular axis of the liquid crystal molecule 21 c is tilted at approximately 45° with respect to each of the transmission axis X 22 of the fourth polarizing plate 22 and the transmission axis X 23 of the third polarizing plate 23 . Further, the short molecular axis of the liquid crystal molecule 21 c is in parallel to a viewing point direction (a direction from the viewing point to the molecule).
  • the liquid crystal display device 10 can be arranged to be in the narrow viewing angle mode in which the image of the display liquid crystal panel 1 is viewed from only a limited viewing point.
  • L 1 through L 8 in FIG. 16 are equipotential lines that show distribution of viewing angles that have luminances of 130 cd/m 2 , 240 cd/m 2 , 350 cd/m 2 , 460 cd/m 2 , 570 cd/m 2 , 680 cd/m 2 , 790 cd/m 2 , and 900 cd/m 2 , respectively.
  • a voltage that is to be applied to the liquid crystal cell 21 of the viewing-angle-control panel 2 is switched at least between two stages of the applied voltage V H and the applied voltage V L . This makes it possible to switch the viewing angle characteristics of the liquid crystal display device 10 between the wide viewing angle mode and the narrow viewing angle mode.
  • a direction of the transmission axis X 23 of the third polarizing plate 23 is set as appropriate by providing the setting retardation plate 7 .
  • the setting retardation plate 7 is a 1 ⁇ 2 ⁇ (wavelength) plate.
  • the setting retardation plate 7 has an effect to shift, by half a wavelength (180 degrees), a phase of one component of the linearly polarized light that is entered. In other words, as illustrated in FIG.
  • the setting retardation plate 7 can convert linearly polarized light Li having a polarization axis that has an angle of ⁇ with respect to an axis A of the setting retardation plate 7 into linearly polarized light Lo having a polarization axis that has an angle of + ⁇ with respect to the axis A of the setting retardation plate 7 .
  • an intensity of the linearly polarized light Li is not changed. This makes it possible to set a direction of the transmission axis of the third polarizing plate 23 as appropriate, by changing an angle of the axis of the setting retardation plate 7 with respect to the transmission axis of the second polarizing plate 12 .
  • an angle of the axis A of the setting retardation plate 7 with respect to the transmission axis X 12 of the second polarizing plate 12 is 0 degree
  • the transmission axis X 23 of the third polarizing plate 23 can be arranged to be at 0 degree with respect to the transmission axis X 12 of the second polarizing plate 12 .
  • the transmission axis X 23 of the third polarizing plate 23 and the transmission axis X 22 of the fourth polarizing plate 22 are substantially orthogonal, the transmission axis X 22 of the fourth polarizing plate 22 is in the same manner as the transmission axis X 22 as illustrated in FIG. 13 .
  • directions of the viewing points P 11 (azimuth angle 0°), P 12 (azimuth angle 90°), and P 14 (azimuth angle 270°) become viewing restricted directions.
  • the display from each of these viewing points becomes a black display.
  • a favorable display can be obtained in the viewing point P 13 (azimuth angle 180°).
  • FIG. 2 An entire arrangement of the liquid crystal display device 10 in this case is illustrated in FIG. 2 .
  • the setting retardation plate 7 is provided so that the axis A of the setting retardation plate 7 becomes parallel to the transmission axis X 12 of the second polarizing plate 12 .
  • the fourth polarizing plate 22 is provided so that the transmission axis X 22 of the fourth polarizing plate 22 intersects substantially orthogonally to the transmission axis X 23 of the third polarizing plate 23 .
  • a direction of the transmission axis X 23 of the third polarizing plate 23 can be set to +45 degrees with respect to the transmission axis X 12 of the second polarizing plate 12 .
  • directions of the viewing points P 22 (azimuth angle 45°), P 24 (azimuth angle 225°), and P 21 (azimuth angle 315°) become viewing restricted directions. In each of these viewing points, the display becomes a black display.
  • FIG. 1 shows an entire arrangement of the liquid crystal display device 10 of this case.
  • the setting retardation plate 7 is provided so that an angle of the axis A of the setting retardation plate 7 with respect to the transmission axis X 12 of the second polarizing plate 12 becomes +22.5 degrees.
  • the transmission axis X 23 of the third polarizing plate 23 can be set at an angle of +45 degrees with respect to the transmission axis X 12 of the second polarizing plate 12 .
  • the fourth polarizing plate 22 can be provided so that the transmission axis X 22 of the fourth polarizing plate 22 intersects substantially orthogonally to the transmission axis X 23 of the third polarizing plate 23 .
  • the liquid crystal display device 10 can change a polarization direction (a direction of the polarization axis) of a linearly polarized light that has transmitted the display liquid crystal panel 1 by use of the setting retardation plate 7 (1 ⁇ 2 wavelength plate).
  • This makes it possible to change the viewing restricted direction by the viewing-angle-control liquid crystal panel 2 . That is, by setting the axis of the setting retardation plate 7 (1 ⁇ 2 wavelength plate) as appropriate, the viewing restricted direction can be set as appropriate.
  • two ⁇ /4 plates may be provided in lieu of the setting retardation plate 7 ( ⁇ /2 plate) as illustrated in FIG. 3 . That is, as illustrated in FIG. 7 , two ⁇ /4 plates 77 a and 77 b are provided in parallel to each other (so that axes of the ⁇ /4 plates 77 a and 77 b become parallel to each other) between the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2 .
  • a retardation plate 25 between the third polarizing plate 23 and the liquid crystal cell 21 and a retardation plate 24 between the liquid crystal cell 21 and the fourth polarizing plate 22 .
  • a retardation plate may be provided either between the third polarizing plate 23 and the liquid crystal cell 21 or between the liquid crystal cell 21 and the fourth polarizing plate 22 .
  • the viewing-angle-control panel 2 is provided above the display liquid crystal panel 1 in the liquid crystal display device of FIG. 3 , the arrangement is not limited to this.
  • the display liquid crystal panel 1 and the viewing-angle-control panel 2 may be laminated in an opposite order. That is, for example, as illustrated in FIG. 11 , it is possible to arrange a liquid crystal display device, by laminating the viewing-angle-control liquid crystal panel 2 above the backlight 3 and further providing the display liquid crystal panel 1 thereon.
  • the liquid crystal cell 21 of the viewing-angle-control liquid crystal panel 2 employs a positive nematic liquid crystal in a homogenous alignment
  • the arrangement is not limited to this.
  • a negative nematic liquid crystal may be used for the liquid crystal cell 21 .
  • behavior of the liquid crystal molecule differs from that in the case of the positive nematic liquid crystal.
  • the liquid crystal molecule becomes perpendicular to the substrate when no voltage is applied, and the liquid crystal molecule is tilted in a direction parallel to the substrate in accordance with the applied voltage. Therefore, a voltage should not applied to the liquid crystal cell of the viewing-angle-control panel in the case of the wide viewing angle, while a predetermined voltage should be applied to the liquid crystal cell in the case of the narrow viewing angle.
  • the liquid crystal display device may be constituted by combining this viewing angle control module 49 with an appropriate display liquid crystal panel 1 .
  • the setting retardation plate 7 ( ⁇ /2 plate) may be fixed to the upper surface of the display liquid crystal panel 1 in advance.
  • the liquid crystal display device of the present embodiment can be constituted by combining the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2 .
  • the present embodiment may have an arrangement in which, as illustrated in FIG. 17 , the setting retardation plate 77 a ( ⁇ /4 plate) is fixed to the upper surface of the display liquid crystal panel 1 in advance and the setting retardation plate 77 b ( ⁇ /4 plate) is fixed to the lower surface of the viewing-angle-control liquid crystal panel 2 in advance.
  • the liquid crystal display device of the present embodiment may be constituted by combining the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2 .
  • the liquid crystal device of the present invention is suitable for a liquid crystal display device in which improvement in privacy protection and security is required.

Abstract

In a liquid crystal display device including a display liquid crystal panel and a viewing-angle-control liquid crystal panel and capable of switching viewing angle characteristics, a half wavelength plate for setting a viewing restricted direction is provided between the display liquid crystal panel and the viewing-angle-control liquid crystal panel. This makes it possible to realize a liquid crystal display device that allows a viewing restricted direction to be set as appropriate.

Description

This application is the U.S. national phase of International Application No. PCT/JP2007/058252, filed 16 Apr. 2007, which designated the U.S. and claims priority to Japan Application No. 2006-217408, filed 9 Aug. 2006, the entire contents of each of which are hereby incorporated by reference.
TECHNICAL FIELD
The present invention relates to a display device (e.g., a liquid crystal display device) capable of switching viewing angle characteristics.
BACKGROUND ART
In general, a display device is required to have a viewing angle characteristic (wide viewing angle characteristic) that allows a sharp image to be viewed from a larger number of viewing points. However, depending on an operation environment, it may be preferable that only a user can view displayed contents. It is highly likely that, for example, a laptop computer, a mobile information terminal (PDA: Personal Data Assistant), or a mobile phone is used in a place, such as a train or an airplane, where the general public is present. In such an operation environment, in view of security protection or privacy protection, it is desirable that the display device takes a viewing angle characteristic (a narrow viewing angle characteristic) with which only a user can view a displayed image (from a limited viewing point) and the surrounding people cannot view the displayed image (from other viewing points).
Recently, it is demanded that one display device is provided with capability of switching between a wide viewing angle characteristic and a narrow viewing angle characteristic.
In response to such a demand, for example, Patent Document 1 discloses a liquid crystal display device in which: a viewing-angle-control liquid crystal panel is provided above a display liquid crystal panel; the viewing-angle-control liquid crystal panel and the display liquid crystal panel are sandwiched by two polarizing plates; and a viewing angle characteristic is controlled by adjusting a voltage that is applied to the viewing-angle-control liquid crystal panel, so that a viewing angle characteristic is controlled.
[Patent Document 1]
Japanese Unexamined Patent Application No. 268251/1998 (Tokukaihei 10-268251) (published on Oct. 9, 1998)
DISCLOSURE OF INVENTION
However, in the conventional liquid crystal display device, a viewing-angle-control liquid crystal panel and an upper polarizing plate need to be provided in accordance with a rubbing direction of a substrate constituting a display liquid crystal panel (or a direction of a polarization axis of a lower polarizing plate). In other words, the display liquid crystal panel determines a direction in which an image can be viewed and a direction in which an image cannot be viewed (viewing restricted direction) in the case of a narrow viewing angle characteristic operation. Therefore, the viewing restricted direction cannot be set unrestrainedly.
The present invention is attained in view of the conventional problem. An object of the present invention is to provide a liquid crystal display device that allows a viewing restricted direction to be set as appropriate.
In order to solve the problem, the liquid crystal display device of the present invention that includes a display liquid crystal panel and a viewing-angle-control liquid crystal panel and that is capable of switching viewing angle characteristics, the liquid crystal display device includes: a retardation member for setting a viewing restricted direction which retardation member being provided between the display liquid crystal panel and the viewing-angle-control liquid crystal panel.
According to the arrangement, an appropriate retardation member (for example, a ½ wavelength plate) is provided between the display liquid crystal panel and the viewing-angle-control liquid crystal panel. This allows changing a polarization direction (a direction of a polarization axis) of a linearly polarized light that has passed through the display liquid crystal panel or the viewing-angle-control liquid crystal panel. This makes it possible to change a viewing restricted direction set by the viewing-angle-control panel. That is, an appropriate retardation member is employed and an axis of the retardation member is set as appropriate. This makes it possible to appropriately set the viewing restricted direction in the case of a narrow viewing characteristic operation.
The liquid crystal display device may have an arrangement in which: the display liquid crystal panel includes a first polarizing member, a display liquid crystal cell, and a second polarizing member overlapped in this order, and the viewing-angle-control liquid crystal panel includes a third polarizing member, a viewing-angle-control liquid crystal cell, and a fourth polarizing member overlapped in this order; and the retardation member is provided between the second polarizing member and the third polarizing member.
The retardation member may be a half wavelength plate (½λ plate). In this case, the second and third polarizing members are provided so that an angle between a transmission axis of the second polarizing plate and an axis of the half wavelength plate becomes equal to an angle between the axis of the half wavelength plate and a transmission axis of the third polarizing plate. According to the arrangement, a polarization direction (a direction of a polarization axis) of a linearly polarized light that has passed through the display liquid crystal panel can be changed while an intensity of the linearly polarized light is kept the same.
The retardation member may be arranged by two ¼ wavelength plates provided in parallel (so that axes of the ¼ wavelength plate become parallel to each other).
The liquid crystal display device may further include: a retardation plate at least either between the first polarizing member and the display liquid crystal cell or between the second polarizing member and the display liquid crystal cell. Moreover, the liquid crystal display device may further include: a retardation plate at least either between the third polarizing member and the viewing-angle-control liquid crystal cell or between the fourth polarizing member and the viewing-angle-control liquid crystal cell. In this way, the retardation plate is provided between a polarizing plate and a liquid crystal cell. This makes it possible to perform optical compensation of an elliptically polarized light. This elliptically polarized light is produced by birefringence that is caused by the liquid crystal cell.
The liquid crystal display device may be provided with a backlight and the display liquid crystal panel provided between the backlight and the viewing-angle-control liquid crystal panel. Moreover, the liquid crystal display device may be provided with a backlight and the viewing-angle-control liquid crystal panel provided between the backlight and the display liquid crystal panel.
In the liquid crystal display device, it is preferable that the light emitted from a backlight has directivity.
A viewing angle control module of the present invention constituting a liquid crystal display device capable of switching, in combination with a display liquid crystal panel, viewing angle characteristics, the viewing angle control module includes: a retardation member for setting a viewing restricted direction and a viewing-angle-control liquid crystal panel which are provided in this order from a side provided with the display liquid crystal panel.
The arrangement makes it possible to change, by use of the retardation member, a polarization direction (a direction of a polarization axis) of the linearly polarized light that has passed through the display liquid crystal panel or the viewing-angle-control liquid crystal panel. As a result, a viewing restricted direction set by the viewing-angle-control liquid crystal panel can be changed. That is, by using an appropriate retardation member and setting an axis of the retardation member appropriately, a viewing restricted direction can be set as appropriate.
In the viewing angle control module, the viewing-angle-control liquid crystal panel may include a first polarizing member, a viewing-angle-control liquid crystal cell, and a second polarizing member overlapped in this order.
In the viewing angle control module, the retardation member may be a half wavelength plate. In this case, an angle between a polarization axis of light that enters the viewing angle control module or exits from the viewing angle control module and an axis of the half wavelength plate is arranged to be equal to an angle between the axis of the half wavelength plate and a transmission axis of the first polarizing plate. According to the arrangement, a polarization direction (a direction of a polarization axis) of a linearly polarized light that has passed through the display liquid crystal panel can be changed while an intensity of the linearly polarized light is kept the same.
The retardation member may be arranged by two ¼ wavelength plates provided in parallel.
As described above, according to the liquid crystal display device of the present invention, an appropriate retardation member (for example, a ½ wavelength plate) is provided between the display liquid crystal panel and the viewing-angle-control liquid crystal panel. This makes it possible to change a polarization direction (a direction of a polarization axis) of a linearly polarized light that has passed through a display. As a result, a viewing restricted direction can be set as appropriate in the case of a narrow viewing angle characteristic operation.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is an exploded perspective view illustrating an example of an arrangement of a liquid crystal display device of the present invention.
FIG. 2 is an exploded perspective view illustrating an example of an arrangement of the liquid crystal display device of the present invention.
FIG. 3 is a cross sectional view illustrating an arrangement an arrangement of the liquid crystal display device of the present invention.
FIG. 4 is a diagram schematically illustrating an effect of a λ/2 plate.
FIG. 5 is a diagram schematically illustrating an effect of a setting retardation plate.
FIG. 6 is a diagram schematically illustrating an effect of a setting retardation plate.
FIG. 7 is a cross sectional view illustrating another arrangement of the liquid crystal display device of the present invention.
FIG. 8 is a cross sectional view illustrating a modified example of the liquid crystal display device of the present invention.
FIG. 9 is a cross sectional view illustrating an arrangement in which a display liquid crystal plate is combined with a viewing-angle-control liquid crystal panel to which a setting retardation plate has been fixed.
FIG. 10 is a cross sectional view illustrating an arrangement in which a viewing-angle-control liquid crystal plate is combined with a display liquid crystal panel to which a setting retardation plate has been fixed.
FIG. 11 is a cross sectional view illustrating an example of an arrangement of the viewing-angle-control liquid crystal panel in the liquid crystal device of the present invention.
FIG. 12( a) is a perspective view illustrating an alignment state of a liquid crystal molecule of the viewing-angle-control panel in a narrow viewing angle mode.
FIG. 12( b) is a perspective view illustrating an alignment state of a liquid crystal molecule of the viewing-angle-control panel in a wide viewing angle mode.
FIG. 13 is a diagram that expresses, in two angles (a polar angle and an azimuth angle), a plurality of viewing points with respect to the viewing-angle-control panel provided in the same direction as the viewing-angle-control panel in each of FIGS. 12( a) and 12(b), and schematically explains each of the plurality of viewing points.
FIG. 14( a) is a diagram illustrating a positional relationship between a liquid crystal molecule and a transmission axis of a polarizing plate in a case where the viewing-angle-control panel is viewed from a viewing point P1.
FIG. 14( b) is a diagram illustrating a positional relationship between the liquid crystal molecule and the transmission axis of the polarizing plate in a case where the viewing-angle-control panel is viewed from a viewing point P2.
FIG. 14( c) is a diagram illustrating a positional relationship between the liquid crystal molecule and the transmission axis of the polarizing plate at the time when the viewing-angle-control panel are viewed from a viewing point P3.
FIG. 15 is a chart illustrating a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the narrow viewing angle mode.
FIG. 16 is a chart illustrating a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the wide viewing angle mode.
FIG. 17 is a cross sectional view illustrating an arrangement in which (i) one λ/4 plate is fixed on an upper surface of the display liquid crystal panel and another λ/4 plate is fixed on a lower surface of the viewing-angle-control liquid crystal panel and (ii) the display liquid crystal panel with the one λ/4 plate is combined with the viewing-angle-control liquid crystal panel with the another λ/4 plate.
 REFERENCE NUMERALS
    • 1 Display Liquid Crystal Panel
    • 2 Viewing-Angle-Control Liquid Crystal Panel
    • 3 Backlight
    • 7 Setting Retardation Plate (λ/2 Plate, Retardation Member)
    • 10 Liquid Crystal Display Device
    • 11 Liquid Crystal Cell
    • 12 Second Polarizing Plate
    • 13 First Polarizing Plate
    • 21 Liquid Crystal Cell
    • 22 Fourth Polarizing Plate
    • 23 Third Polarizing Plate
    • 24 Retardation Plate
    • 25 Retardation Plate
    • 49 Viewing Angle Control Module
    • 77 a λ/4 Plate (Retardation Member)
    • 77 b λ/4 Plate (Retardation Member)
    • X12 Transmission Axis
    • X22 Transmission Axis
    • X23 Transmission Axis
    • A Axis of Setting Retardation Plate (λ/2 Plate)
BEST MODE FOR CARRYING OUT THE INVENTION
The following explains one embodiment of the present invention, with reference to FIGS. 1 through 17.
FIG. 3 is a cross sectional view schematically illustrating a liquid crystal display device 10 of the present invention. As illustrated in FIG. 3, the liquid crystal display device 10 includes a display liquid crystal panel 1 that displays an image, a viewing-angle-control liquid crystal panel 2 that switches viewing angle characteristics of the liquid crystal display device 10, a setting retardation plate (½λ plate) 7 that is provided between the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2 for setting a viewing restricted direction, and a backlight 3.
In the display liquid crystal panel 1, a first polarizing plate 13, a display liquid crystal cell 11 in which a liquid crystal is sandwiched by a pair of light-transmitting substrates, and a second polarizing plate 12 are provided in this order. In the viewing-angle-control liquid crystal panel 2, a third polarizing plate 23, a viewing-angle-control liquid crystal cell 21 in which a liquid crystal is sandwiched by a pair of light-transmitting substrates are provided in this order. The setting retardation plate 7 is provided between the second polarizing plate 12 and the third polarizing plate 23.
The liquid crystal display device 10 can take a wide viewing angle mode (wide viewing angle characteristic) and a narrow viewing angle mode (narrow viewing angle characteristic), by a switching operation of the liquid crystal provided in the viewing-angle-control liquid crystal cell 21. In the wide viewing angle mode, an image of the display liquid crystal panel 1 can be viewed from a larger number of viewing points. In the narrow viewing angle mode, the image of the display liquid crystal panel can be viewed from only a limited viewing point. The narrow viewing angle mode is suitable in a case where it is unfavorable that the image of the display liquid crystal panel 1 is viewed by others. Meanwhile, the wide viewing angle mode is suitable, for example, in general use or in a case where an image of the display liquid crystal panel 1 is desired to be viewed simultaneously by a plurality of people.
A liquid crystal mode, a cell structure, and a driving mode of the display liquid crystal panel 1 may be determined as appropriate. That is, any liquid crystal panel (for example, a TN liquid crystal panel or an ASV liquid crystal panel) capable of displaying a character, an image, or a moving image may be used as the display liquid crystal panel 1. The display liquid crystal panel 1 may also be a semi-transmissive liquid crystal panel. Further, the display liquid crystal panel 1 may be a panel capable of performing color display or a panel exclusive to monochrome display. An arrangement of the backlight 3 is also determined as appropriate. For example, the backlight 3 may be a backlight that emits light having directivity.
A liquid crystal layer of the viewing-angle-control liquid crystal cell 21 is made of, for example, a positive nematic liquid crystal in a homogenous alignment. A surface of the second polarizing plate 12 may be subjected to a diffusion treatment such as an AG treatment. The first polarizing plate 13 is a so-called a clear polarizing plate that is not subjected to a surface treatment.
With reference to FIGS. 12( a) and 12(b), an arrangement and an operation of the viewing-angle-control liquid crystal panel 2 are explained. FIGS. 12( a) and 12(b) are diagrams each schematically illustrating mainly an arrangement of the viewing-angle-control liquid crystal panel 2. FIG. 12( a) shows an alignment state of a liquid crystal molecule of the viewing-angle-control panel in the narrow viewing angle mode. FIG. 12( b) shows an alignment state of a liquid crystal molecule of the viewing-angle-control panel in the wide viewing angle mode.
As illustrated in FIGS. 12( a) and 12(b), the viewing-angle-control liquid crystal cell 21 includes a pair of light-transmitting substrates 21 a and 21 b. On surfaces of the light-transmitting substrates 21 a and 21 b, transparent electrodes (not illustrated) are formed by use of, for example, ITO (Indium Tin Oxide), respectively. Because the display liquid crystal cell 11 needs to drive a liquid crystal for each display unit such as a pixel unit or a segment unit, the display liquid crystal cell 11 has an electrode structure in accordance with the display unit. On the other hand, an electrode arrangement of the viewing-angle-control liquid crystal cell 21 is not limited. The viewing-angle-control liquid crystal cell 21 may have, for example, an arrangement in which uniform electrodes are formed on an entire surface of each of the light-transmitting substrates 21 a and 21 b for carrying out uniform switching all over a display surface or other appropriate electrode arrangement.
On an upper layer of the transparent electrode, an alignment film (not illustrated) is formed. This alignment film aligns liquid crystal molecules 21 c. The alignment film is subjected to a rubbing treatment according to a publicly known method. Arrows Ra and Rb in FIGS. 12( a) and 12(b) shows rubbing directions of the light-transmitting substrates 21 a and 21 b, respectively. As illustrated in FIGS. 12( a) and 12(b), the rubbing direction Ra with respect to the alignment film of the light-transmitting substrate 21 a is substantially parallel and in a reverse direction with respect to the rubbing direction Rb with respect to the alignment film of the light-transmitting substrate 21 b.
In other words, the viewing-angle-control liquid crystal device 21 (hereinafter, referred to as a liquid crystal cell 21 as appropriate) is a so-called parallel cell that has a twist angle of 0 (no twist). In the present embodiment, the liquid crystal provided in the liquid crystal cell 21 is a liquid crystal in a homogenous alignment. Accordingly, each of the liquid crystal molecules 21 c of the liquid crystal cell 21 is aligned so that a long molecular axis becomes parallel to a substrate surface of each of the substrates 21 a and 21 b at the time when no voltage is applied. A retardation value d·Δn (d is a thickness of the cell, and Δn is a birefringence) of the liquid crystal layer of the liquid crystal cell 21 is, for example, in a range of 350 nm to 450 nm.
When a voltage is applied between electrodes (not illustrated) that are provided on the light-transmitting substrates 21 a and 21 b, respectively, the liquid crystal molecules 21 c gradually changes a direction according to a size of the applied voltage. The liquid crystal molecule 21 c changes the direction from a state parallel to the substrate surface, within a plane that is perpendicular to a normal of each of the light-transmitting substrates 21 a and 21 b as illustrated in FIG. 12( a) and parallel to the respective rubbing directions Ra and Rb with respect to the alignment films of the light-transmitting substrates 21 a and 21 b. When the applied voltage reaches a predetermined value, the liquid crystal molecule 21 c is oriented in a state in which the long molecular axis is substantially perpendicular to the substrate surface of each of the light-transmitting substrates 21 a and 21 b. That is, FIG. 12( a) shows a state in which the long molecular axis of the liquid crystal molecule 21 c is slightly tilted with respect to the normal of each of the light-transmitting substrate 21 a and 21 b due to an applied voltage VL (a voltage in a range of, for example, approximately 2.5 V to 3.5 V). FIG. 12( b) shows a state in which the long molecular axis of the liquid crystal molecule 21 c is substantially perpendicular with respect to the substrate surface of each of the light-transmitting substrate 21 a and 21 b due to an applied voltage VH (a voltage, for example, not less than 5.0 V).
As illustrated in FIG. 12( a), in the viewing-angle-control panel 2, the third polarizing plate 23 provided below the liquid crystal cell 21 and the fourth polarizing plate 22 provided above the liquid crystal cell 21 are provided so that a transmission axis X23 of the polarizing plate 22 and a transmission axis X22 of the polarizing plate 23 become substantially orthogonal.
In a case where the transmission axis X23 and the transmission axis X22 are arranged to be substantially orthogonal in this way (that is, an angle between the transmission axis X22 and the transmission axis X23 is in a range of 800 to 100°), a sufficient effect can be obtained from switching viewing angles. The transmission axis X22 of the fourth polarizing plate 22 keeps tilt at an angle in a range of 40° to 50° (preferably 45°).
Here, with reference to FIG. 13 and FIGS. 14( a) through 14(c), in addition to the above-explained FIGS. 12( a) and 12(b), the following explains a principle of switching the viewing angle characteristics of the liquid crystal display device 10 between the wide viewing angle mode and the narrow viewing angle mode, by using the viewing-angle-control panel 2. In the following explanation, a viewing point with respect to the viewing-angle-control panel 2 is expressed in an azimuth angle θ and a polar angle φ that use a center of the fourth polarizing plate 22 as a reference. Here, the azimuth angle θ is a rotational angle of a line connecting between a center 22 c of the fourth polarizing plate 22 a and a point at which a perpendicular line from a viewing point to a plane including a surface of the fourth polarizing plate 22 intersects with the plane. The polar angle φ is an angle between a line connecting the center 22 c of the fourth polarizing plate 22 with the viewing point and a normal of the fourth polarizing plate 22.
FIG. 13 shows three viewing points P1 through P3 with respect to the viewing-angle-control panel 2 that is provided in the same direction as that in FIGS. 12( a) and 12(b). The azimuth angle θ increases clockwise in a case where the viewing-angle-control panel 2 is viewed from an upper side in a normal direction of the fourth polarizing plate 22, on an assumption that the azimuth angle of the viewing point P1 is 0°. As illustrated in FIG. 13, the viewing point P1 is expressed in the azimuth angle θ1=0° and the polar angle=φ1. The viewing point P2 is expressed in the azimuth angle θ2=90° and the polar angle=φ2. The viewing point P3 is expressed in the azimuth angle θ3=180° and the polar angle=φ3.
With reference to FIGS. 14( a) through 14(c), the following explains display states that are observed from the viewing points P1 through P3 shown in FIG. 13, respectively, in a case where the long molecular axis of the liquid crystal molecule 21 c is tilted, due to the applied voltage VL that is applied to the liquid crystal cell 21, at a slight angle with respect to the normal of each of the light-transmitting substrates 21 a and 21 b (in the case of FIG. 12( a)). FIG. 15 is a chart illustrating a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the narrow viewing angle mode. FIG. 16 is a viewing angle characteristic (dependency of luminance distribution on the polar angle and the azimuth angle) in the wide viewing angle mode.
When the viewing-angle-control panel 2 is viewed from the viewing point P1 (azimuth angle θ1=0° and polar angle=φ1) of FIG. 13, the liquid crystal molecule 21 c is, as illustrated in FIG. 14( a), in a state in which the long molecular axis of the liquid crystal molecule 21 c is in parallel to a viewing point direction (a direction from the viewing point to the molecule). Consequently, a linearly polarized light that passes through the third polarizing plate 23 and enters the liquid crystal cell 21 toward the viewing point P1 is not given birefringence by the liquid crystal molecule 21 c. As a result, the fourth polarizing plate 22 shields the linearly polarized light. Accordingly, a display viewed from the viewing point P1 becomes a black display. In a case where the applied voltage VL that is applied to the liquid crystal cell 21 is in a range of approximately 2.5 V to 3.5 V, a sufficient light-shielding state for preventing others from peeking at the display is obtained, as illustrated in FIG. 15, at the polar angle φ in a range of approximately 30°≦φ<90° in the case of the azimuth angle θ1=0°. In other words, a direction expressed in the azimuth angle θ1=0° with respect to the center 22 c of the fourth polarizing plate 22 becomes a viewing restricted direction.
L1 through L8 in FIG. 15 are equipotential lines that show distribution of viewing angles that have luminances of 50 cd/m2, 100 cd/m2, 150 cd/m2, 200 cd/m2, 250 cd/m2, 300 cd/m2, 350 cd/m2, and 400 cd/m2, respectively.
When the viewing-angle-control panel 2 is viewed from the viewing point P2 (azimuth angle θ2=90° and polar angle=φ2) of FIG. 13, the liquid crystal molecule 21 c is, as illustrated in FIG. 14( b), in a state in which the long molecular axis of the liquid crystal molecule 21 c is slightly tilted with respect to each of the transmission axis X22 of the third polarizing plate 22 and the transmission axis X23 of the third polarizing plate 23. Consequently, a very slight birefringence is produced by the liquid crystal molecule 21 c in a linearly polarized light that passes through the third polarizing plate 23 and enters the liquid crystal cell 21 toward the viewing point P2. However, the fourth polarizing plate 22 shields the linearly polarized light. Accordingly, a display viewed from the viewing point P2 also becomes a black display. Moreover, a display viewed from a position opposed to the viewing point P2, that is, a display in a case where the azimuth angle θ is 270°, also becomes a black display, because of the same principle as in the observation from the viewing point P2. In a case where the applied voltage VL that is applied to the liquid crystal cell 21 is in a range of approximately 2.5 V to 3.5 V, a sufficient light-shielding state for preventing others from peeking at the display is obtained, as illustrated in FIG. 15, at the polar angle φ in a range of approximately 30°≦φ<90° in the case of the azimuth angles θ=90° and 270°. In other words, directions that are expressed in the azimuth angles θ2=90° and 270°, respectively, with respect to the center 22 c of the fourth polarizing plate 22 become viewing restricted directions.
When the viewing-angle-control panel 2 is viewed from the viewing point P3 (azimuth angle θ3=180° and polar angle=φ3) of FIG. 13, the liquid crystal molecule 21 c is, as illustrated in FIG. 14( c), in a state in which the long molecular axis of the liquid crystal molecule 21 c is tilted at approximately 45° with respect to each of the transmission axis X22 of the fourth polarizing plate 22 and the transmission axis X23 of the third polarizing plate 23. Further, the short molecular axis of the liquid crystal molecule 21 c is in parallel to a viewing point direction (a direction from the viewing point to the molecule). Consequently, birefringence is given by the liquid crystal molecule 21 c to a linearly polarized light that passes through the third polarizing plate 23 and enters the liquid crystal cell 21 toward the viewing point P3. This rotates the polarization axis (polarization direction) of the linearly polarized light so that the polarization axis agrees with the transmission axis X22 of the fourth polarizing plate 22. As a result, the linearly polarized light passes through the fourth polarizing plate 22. Therefore, a favorable display can be obtained at the viewing point P2. In a case where the applied voltage VL that is applied to the liquid crystal cell 21 is in a range of approximately 2.5 V to 3.5 V as described above, a favorable display can be obtained as illustrated in FIG. 15, at the polar angle φ in a range of approximately 0°≦φ<90° in the case of the azimuth angle θ3=180°. In other words, a direction that is expressed in the azimuth angle θ3=180° with respect to the center 22 c of the fourth polarizing plate 22 becomes a viewing restricted direction.
As explained above, when the applied voltage VL is applied to the liquid crystal cell 21 of the viewing-angle-control liquid crystal panel 2 which applied voltage VL tilts the long molecular axis of the liquid crystal molecule 21 c at a slight angle with respect to a substrate normal (in the case of FIG. 12( a)), a favorable display is obtained only at the azimuth angle θ in a narrow range around 180°. In other azimuth angles, the polarized light in the liquid crystal cell 21 is shielded by the fourth polarizing plate 22, and the display becomes a black display. That is, the liquid crystal display device 10 can be arranged to be in the narrow viewing angle mode in which the image of the display liquid crystal panel 1 is viewed from only a limited viewing point.
On the other hand, when, as illustrated in FIG. 12( b), an applied voltage VH is applied to the liquid crystal cell 21 of the viewing-angle-control panel 2 which applied voltage VH tilts the long molecular axis of the liquid crystal molecule 21 c to substantially perpendicular to the substrate, sufficient birefringence that provides a favorable display occurs in light traveling towards any of the viewing points P1 through P3 as illustrated in FIG. 13. In other words, as illustrated in FIG. 16, substantially all azimuth angles θ with respect to the center 22 c of the fourth polarizing plate 22 become viewing allowing directions. This allows arranging the liquid crystal display device 10 to be in the wide viewing angle mode in which the image of the display liquid crystal panel 1 can be viewed from a larger number of viewing points. L1 through L8 in FIG. 16 are equipotential lines that show distribution of viewing angles that have luminances of 130 cd/m2, 240 cd/m2, 350 cd/m2, 460 cd/m2, 570 cd/m2, 680 cd/m2, 790 cd/m2, and 900 cd/m2, respectively.
In this way, in the liquid crystal display device 10 of the present embodiment, a voltage that is to be applied to the liquid crystal cell 21 of the viewing-angle-control panel 2 is switched at least between two stages of the applied voltage VH and the applied voltage VL. This makes it possible to switch the viewing angle characteristics of the liquid crystal display device 10 between the wide viewing angle mode and the narrow viewing angle mode.
In the liquid crystal display device 10, a direction of the transmission axis X23 of the third polarizing plate 23 is set as appropriate by providing the setting retardation plate 7. This allows the viewing restricted direction in the narrow viewing angle mode to be set as appropriate. Here, the setting retardation plate 7 is a ½λ (wavelength) plate. In a case where the linearly polarized light decomposed into two component sign waves is considered, the setting retardation plate 7 has an effect to shift, by half a wavelength (180 degrees), a phase of one component of the linearly polarized light that is entered. In other words, as illustrated in FIG. 4, the setting retardation plate 7 can convert linearly polarized light Li having a polarization axis that has an angle of −α with respect to an axis A of the setting retardation plate 7 into linearly polarized light Lo having a polarization axis that has an angle of +α with respect to the axis A of the setting retardation plate 7. In this conversion, an intensity of the linearly polarized light Li is not changed. This makes it possible to set a direction of the transmission axis of the third polarizing plate 23 as appropriate, by changing an angle of the axis of the setting retardation plate 7 with respect to the transmission axis of the second polarizing plate 12.
For example, as illustrated in FIG. 6, an angle of the axis A of the setting retardation plate 7 with respect to the transmission axis X12 of the second polarizing plate 12 is 0 degree, the transmission axis X23 of the third polarizing plate 23 can be arranged to be at 0 degree with respect to the transmission axis X12 of the second polarizing plate 12. Moreover, because the transmission axis X23 of the third polarizing plate 23 and the transmission axis X22 of the fourth polarizing plate 22 are substantially orthogonal, the transmission axis X22 of the fourth polarizing plate 22 is in the same manner as the transmission axis X22 as illustrated in FIG. 13. Accordingly, in the narrow viewing angle mode, directions of the viewing points P11 (azimuth angle 0°), P12 (azimuth angle 90°), and P14 (azimuth angle 270°) become viewing restricted directions. The display from each of these viewing points becomes a black display. On the other hand, a favorable display can be obtained in the viewing point P13 (azimuth angle 180°). An entire arrangement of the liquid crystal display device 10 in this case is illustrated in FIG. 2. As illustrated in FIG. 2, the setting retardation plate 7 is provided so that the axis A of the setting retardation plate 7 becomes parallel to the transmission axis X12 of the second polarizing plate 12. This makes it possible to set the transmission axis X23 of the third polarizing plate 23 to be parallel to the transmission axis X12 of the second polarizing plate 12. Moreover, the fourth polarizing plate 22 is provided so that the transmission axis X22 of the fourth polarizing plate 22 intersects substantially orthogonally to the transmission axis X23 of the third polarizing plate 23.
In a case where, as illustrated in FIG. 5, an angle the axis A of the setting retardation plate 7 with respect to the transmission axis X12 of the second polarizing plate 12 is set to +22.5 degrees, a direction of the transmission axis X23 of the third polarizing plate 23 can be set to +45 degrees with respect to the transmission axis X12 of the second polarizing plate 12. As a result, directions of the viewing points P22 (azimuth angle 45°), P24 (azimuth angle 225°), and P21 (azimuth angle 315°) become viewing restricted directions. In each of these viewing points, the display becomes a black display. On the other hand, a favorable display can be obtained at the viewing point P23 (azimuth angle 135°). FIG. 1 shows an entire arrangement of the liquid crystal display device 10 of this case. As illustrated in FIG. 1, the setting retardation plate 7 is provided so that an angle of the axis A of the setting retardation plate 7 with respect to the transmission axis X12 of the second polarizing plate 12 becomes +22.5 degrees. As a result, the transmission axis X23 of the third polarizing plate 23 can be set at an angle of +45 degrees with respect to the transmission axis X12 of the second polarizing plate 12. Moreover, the fourth polarizing plate 22 can be provided so that the transmission axis X22 of the fourth polarizing plate 22 intersects substantially orthogonally to the transmission axis X23 of the third polarizing plate 23.
In this way, the liquid crystal display device 10 can change a polarization direction (a direction of the polarization axis) of a linearly polarized light that has transmitted the display liquid crystal panel 1 by use of the setting retardation plate 7 (½ wavelength plate). This makes it possible to change the viewing restricted direction by the viewing-angle-control liquid crystal panel 2. That is, by setting the axis of the setting retardation plate 7 (½ wavelength plate) as appropriate, the viewing restricted direction can be set as appropriate.
In the viewing angle control panel 2 of the liquid crystal display device 10, two λ/4 plates may be provided in lieu of the setting retardation plate 7 (λ/2 plate) as illustrated in FIG. 3. That is, as illustrated in FIG. 7, two λ/4 plates 77 a and 77 b are provided in parallel to each other (so that axes of the λ/4 plates 77 a and 77 b become parallel to each other) between the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2.
Alternatively, as illustrated in FIG. 8, in the viewing-angle-control panel 2 of the liquid crystal display device 10, it is possible to provide a retardation plate 25 between the third polarizing plate 23 and the liquid crystal cell 21 and a retardation plate 24 between the liquid crystal cell 21 and the fourth polarizing plate 22. Further, a retardation plate may be provided either between the third polarizing plate 23 and the liquid crystal cell 21 or between the liquid crystal cell 21 and the fourth polarizing plate 22. By providing the retardation plate between the polarizing plate and the liquid crystal cell in this way, optical compensation of an elliptically polarized light becomes possible. This elliptically polarized light is produced by birefringence caused by the liquid crystal cell 21. As a result, light leakage can be suppressed. This can improve the viewing angle characteristic in the narrow viewing angle mode. Note that, as illustrated in FIG. 8, it is possible to provide a retardation plate 28 between the first polarizing plate 13 and the liquid crystal cell 11 and a retardation plate 27 between the liquid crystal cell 11 and the second polarizing plate 12.
Though the viewing-angle-control panel 2 is provided above the display liquid crystal panel 1 in the liquid crystal display device of FIG. 3, the arrangement is not limited to this. For example, the display liquid crystal panel 1 and the viewing-angle-control panel 2 may be laminated in an opposite order. That is, for example, as illustrated in FIG. 11, it is possible to arrange a liquid crystal display device, by laminating the viewing-angle-control liquid crystal panel 2 above the backlight 3 and further providing the display liquid crystal panel 1 thereon.
Though the liquid crystal cell 21 of the viewing-angle-control liquid crystal panel 2 employs a positive nematic liquid crystal in a homogenous alignment, the arrangement is not limited to this. For example, a negative nematic liquid crystal may be used for the liquid crystal cell 21. Note that, in a case where the negative nematic liquid crystal is used, behavior of the liquid crystal molecule differs from that in the case of the positive nematic liquid crystal. In the case of the negative nematic liquid crystal, the liquid crystal molecule becomes perpendicular to the substrate when no voltage is applied, and the liquid crystal molecule is tilted in a direction parallel to the substrate in accordance with the applied voltage. Therefore, a voltage should not applied to the liquid crystal cell of the viewing-angle-control panel in the case of the wide viewing angle, while a predetermined voltage should be applied to the liquid crystal cell in the case of the narrow viewing angle.
In the present embodiment, as illustrated in FIG. 9, after the setting retardation plate 7 (λ/2 plate) is fixed to a lower surface of the viewing-angle-control liquid crystal panel 2 so as to constitute a viewing angle control module 49, the liquid crystal display device may be constituted by combining this viewing angle control module 49 with an appropriate display liquid crystal panel 1.
In the same manner, in the present embodiment, as illustrated in FIG. 10, the setting retardation plate 7 (λ/2 plate) may be fixed to the upper surface of the display liquid crystal panel 1 in advance. In other words, after the display liquid crystal panel 1 to which the setting retardation plate 7 (λ/2 plate) is fixed and the viewing-angle-control liquid crystal panel 2 are arranged separately, the liquid crystal display device of the present embodiment can be constituted by combining the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2.
Further, the present embodiment may have an arrangement in which, as illustrated in FIG. 17, the setting retardation plate 77 a (λ/4 plate) is fixed to the upper surface of the display liquid crystal panel 1 in advance and the setting retardation plate 77 b (λ/4 plate) is fixed to the lower surface of the viewing-angle-control liquid crystal panel 2 in advance. In other words, after the display liquid crystal panel 1 to which the setting retardation plate 77 b (λ/4 plate) is fixed and the viewing-angle-control liquid crystal panel to which the setting retardation plate 77 a (λ/4 plate) is fixed are separately arranged, the liquid crystal display device of the present embodiment may be constituted by combining the display liquid crystal panel 1 and the viewing-angle-control liquid crystal panel 2.
INDUSTRIAL APPLICABILITY
The liquid crystal device of the present invention is suitable for a liquid crystal display device in which improvement in privacy protection and security is required.

Claims (8)

1. A liquid crystal display device that is capable of switching viewing angle characteristics, the liquid crystal display device comprising:
a viewing-angle-control liquid crystal panel provided on a viewing surface side between a viewing surface and a backlight, the viewing-angle-control liquid crystal panel including a fourth polarizing member, a viewing-angle-control liquid crystal cell, and a third polarizing member provided in this order so as to be at least partially overlapped from the viewing surface;
a display liquid crystal panel provided on a backlight side between the viewing surface and the backlight, the display liquid crystal panel including a second polarizing member, a display liquid crystal cell, and a first polarizing member provided in this order so as to be at least partially overlapped from the viewing surface; and
a retardation member for setting a viewing restricted direction, the retardation member provided between at least the third polarizing member and the second polarizing member,
the fourth polarizing member having a transmission axis in a direction that is different from a direction of a transmission axis of the second polarizing member.
2. The liquid crystal display device as set forth in claim 1 wherein the retardation member is a half wavelength plate.
3. The liquid crystal display device as set forth in claim 1 wherein the retardation member is made of two parallel ¼ wavelength plates.
4. The liquid crystal display device as set forth in claim 2 wherein:
the second and third polarizing members are provided so that an angle between a transmission axis of the third polarizing member and an axis of the half wavelength plate becomes equal to an angle between the axis of the half wavelength plate and a transmission axis of the second polarizing member.
5. The liquid crystal display device as set forth in claim 1, further comprising:
a retardation plate at least either between the fourth polarizing member and the viewing-angle-control liquid crystal cell or between the viewing-angle-control liquid crystal cell and the third polarizing member.
6. The liquid crystal display device as set forth in claim 1, further comprising:
a retardation plate at least either between the second polarizing member and the display liquid crystal cell or between the display liquid crystal cell and the first polarizing member.
7. The liquid crystal display device as set forth in claim 1, further comprising:
a backlight emitting light that has directivity.
8. A liquid crystal display device that is capable of switching viewing angle characteristics, the liquid crystal display device comprising:
a display liquid crystal panel provided on a viewing surface side between a viewing surface and a backlight, the display liquid crystal panel including a second polarizing member, a display liquid crystal cell, and a first polarizing member provided in this order so as to be at least partially overlapped from the viewing surface;
a viewing-angle-control liquid crystal panel provided on a backlight side between the viewing surface and the backlight, the viewing-angle-control liquid crystal panel including a fourth polarizing member, a viewing-angle-control liquid crystal cell, and a third polarizing member provided in this order so as to be at least partially overlapped from the viewing surface; and
a retardation member for setting a viewing restricted direction, the retardation member provided between at least the first polarizing member and the fourth polarizing member,
the second polarizing member having a transmission axis in a direction that is different from a direction of a transmission axis of the fourth polarizing member.
US12/297,922 2006-08-09 2007-04-16 Liquid crystal display device and viewing angle control module Expired - Fee Related US8045097B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2006217408 2006-08-09
JP2006-217408 2006-08-09
PCT/JP2007/058252 WO2008018212A1 (en) 2006-08-09 2007-04-16 Liquid crystal display device and viewing angle control module

Publications (2)

Publication Number Publication Date
US20090174843A1 US20090174843A1 (en) 2009-07-09
US8045097B2 true US8045097B2 (en) 2011-10-25

Family

ID=39032750

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/297,922 Expired - Fee Related US8045097B2 (en) 2006-08-09 2007-04-16 Liquid crystal display device and viewing angle control module

Country Status (7)

Country Link
US (1) US8045097B2 (en)
EP (1) EP2051134A4 (en)
JP (1) JP5037508B2 (en)
KR (1) KR20090017499A (en)
CN (1) CN101427177B (en)
HK (1) HK1128966A1 (en)
WO (1) WO2008018212A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090317773A1 (en) * 2008-06-24 2009-12-24 United States Of America As Represented By The Administrator Of The N.A.S.A. Variably Transmittive, Electronically-Controlled Eyewear
US20100060824A1 (en) * 2007-01-31 2010-03-11 Takehiko Sakai Viewing angle controlling liquid crystal panel and display device
US20120044430A1 (en) * 2010-08-18 2012-02-23 Chunghwa Picture Tubes, Ltd. 3D Image Display Device
US20180143468A1 (en) * 2015-05-27 2018-05-24 Panasonic Intellectual Property Management Co., Ltd. Optical device

Families Citing this family (50)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI356937B (en) * 2007-07-20 2012-01-21 Chimei Innolux Corp Viewing angle controllable liquid crystal display
CN103792742A (en) * 2014-01-23 2014-05-14 京东方科技集团股份有限公司 Liquid crystal display device
US10782556B2 (en) 2015-07-29 2020-09-22 Sharp Kabushiki Kaisha Sunlight readable LCD with uniform in-cell retarder
US10591767B2 (en) 2015-07-29 2020-03-17 Sharp Kabushiki Kaisha Sunlight readable LCD with uniform in-cell retarder
CN105116600B (en) * 2015-09-16 2018-06-01 昆山龙腾光电有限公司 Liquid crystal display and display device
EP3369034B1 (en) 2015-10-26 2023-07-05 RealD Spark, LLC Intelligent privacy system, apparatus, and method thereof
CN109416431B (en) 2016-05-19 2022-02-08 瑞尔D斯帕克有限责任公司 Wide-angle imaging directional backlight
TWI606286B (en) * 2016-05-24 2017-11-21 揚昇照明股份有限公司 Composite film and display device
TWM537663U (en) * 2016-10-25 2017-03-01 揚昇照明股份有限公司 Viewing angle control device and viewing angle controllable display apparatus
TWI605287B (en) 2016-12-29 2017-11-11 揚昇照明股份有限公司 Display Device
CN108345139B (en) 2017-01-25 2022-04-22 中强光电股份有限公司 Display device with switchable viewing angle
EP3622342A4 (en) 2017-05-08 2021-02-17 RealD Spark, LLC Optical stack for directional display
US10126575B1 (en) 2017-05-08 2018-11-13 Reald Spark, Llc Optical stack for privacy display
WO2018221413A1 (en) * 2017-05-29 2018-12-06 富士フイルム株式会社 Display device
CN107329316A (en) * 2017-09-01 2017-11-07 东莞通华液晶有限公司 A kind of high information quantity liquid crystal display structure
TW201921060A (en) 2017-09-15 2019-06-01 美商瑞爾Ｄ斯帕克有限責任公司 Optical stack for switchable directional display
US10948648B2 (en) 2017-09-29 2021-03-16 Reald Spark, Llc Backlights having stacked waveguide and optical components with different coefficients of friction
EP3707554B1 (en) 2017-11-06 2023-09-13 RealD Spark, LLC Privacy display apparatus
JP6887525B2 (en) * 2017-11-27 2021-06-16 富士フイルム株式会社 Display device
CN207650518U (en) 2017-12-26 2018-07-24 扬升照明股份有限公司 Display module can be switched in visual angle switchable apparatus and visual angle
EP3736621A4 (en) * 2018-01-04 2020-12-09 Lg Chem, Ltd. Liquid crystal display device and manufacturing method thereof
CA3089477A1 (en) * 2018-01-25 2019-08-01 Reald Spark, Llc Touch screen for privacy display
US10976578B2 (en) * 2018-01-25 2021-04-13 Reald Spark, Llc Reflective optical stack for privacy display
CN112075076B (en) 2018-03-22 2023-05-02 瑞尔D斯帕克有限责任公司 Light guide for directional backlight
CN110361883B (en) 2018-03-26 2023-04-28 中强光电股份有限公司 Peep-proof control device, backlight module and display using peep-proof control device
CN208126055U (en) 2018-04-28 2018-11-20 扬升照明股份有限公司 Display device
WO2020005748A1 (en) 2018-06-29 2020-01-02 Reald Spark, Llc Optical stack for privacy display
US11073735B2 (en) 2018-07-18 2021-07-27 Reald Spark, Llc Optical stack for switchable directional display
US11106103B2 (en) 2018-10-03 2021-08-31 Reald Spark, Llc Privacy display apparatus controlled in response to environment of apparatus
US11092852B2 (en) 2018-11-07 2021-08-17 Reald Spark, Llc Directional display apparatus
WO2020146091A1 (en) 2019-01-07 2020-07-16 Reald Spark, Llc Optical stack for privacy display
WO2020167680A1 (en) 2019-02-12 2020-08-20 Reald Spark, Llc Diffuser for privacy display
TW202102883A (en) 2019-07-02 2021-01-16 美商瑞爾Ｄ斯帕克有限責任公司 Directional display apparatus
CN114341681A (en) 2019-08-02 2022-04-12 瑞尔D斯帕克有限责任公司 Optical stack for privacy display
WO2021067638A1 (en) 2019-10-02 2021-04-08 Reald Spark, Llc Privacy display apparatus
CN114868050A (en) 2019-11-13 2022-08-05 瑞尔D斯帕克有限责任公司 Display device with uniform off-axis brightness reduction
JP7395328B2 (en) * 2019-11-14 2023-12-11 株式会社ジャパンディスプレイ Vehicle display device
CN114761844A (en) 2019-12-10 2022-07-15 瑞尔D斯帕克有限责任公司 Control of reflection of display device
WO2021126707A1 (en) 2019-12-18 2021-06-24 Reald Spark, Llc Control of ambient light for a privacy display
CN113311600B (en) 2020-02-26 2024-02-06 中强光电股份有限公司 Display device
WO2021222598A1 (en) 2020-04-30 2021-11-04 Reald Spark, Llc Directional display apparatus
US11668963B2 (en) 2020-04-30 2023-06-06 Reald Spark, Llc Directional display apparatus
CN115997146A (en) 2020-04-30 2023-04-21 瑞尔D斯帕克有限责任公司 Directional display device
WO2022026536A1 (en) 2020-07-29 2022-02-03 Reald Spark, Llc Backlight for switchable directional display
TW202204818A (en) 2020-07-29 2022-02-01 美商瑞爾Ｄ斯帕克有限責任公司 Pupillated illumination apparatus
CN114384714A (en) * 2020-10-18 2022-04-22 中强光电股份有限公司 Display device
CN115561932A (en) * 2021-07-02 2023-01-03 中强光电股份有限公司 Backlight module and display device
US11892717B2 (en) 2021-09-30 2024-02-06 Reald Spark, Llc Marks for privacy display
US11841585B2 (en) * 2021-12-02 2023-12-12 Coretronic Corporation Display apparatus and method of driving the same
US11892718B2 (en) 2022-04-07 2024-02-06 Reald Spark, Llc Directional display apparatus

Citations (43)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4373784A (en) 1979-04-27 1983-02-15 Sharp Kabushiki Kaisha Electrode structure on a matrix type liquid crystal panel
US4662746A (en) 1985-10-30 1987-05-05 Texas Instruments Incorporated Spatial light modulator and method
US4811003A (en) 1987-10-23 1989-03-07 Rockwell International Corporation Alternating parallelogram display elements
US4956619A (en) 1988-02-19 1990-09-11 Texas Instruments Incorporated Spatial light modulator
US5061049A (en) 1984-08-31 1991-10-29 Texas Instruments Incorporated Spatial light modulator and method
US5083857A (en) 1990-06-29 1992-01-28 Texas Instruments Incorporated Multi-level deformable mirror device
US5146356A (en) 1991-02-04 1992-09-08 North American Philips Corporation Active matrix electro-optic display device with close-packed arrangement of diamond-like shaped
US5309241A (en) 1992-01-24 1994-05-03 Loral Fairchild Corp. System and method for using an anamorphic fiber optic taper to extend the application of solid-state image sensors
US5317409A (en) 1991-12-03 1994-05-31 North American Philips Corporation Projection television with LCD panel adaptation to reduce moire fringes
US5386253A (en) 1990-04-09 1995-01-31 Rank Brimar Limited Projection video display systems
US5402184A (en) 1993-03-02 1995-03-28 North American Philips Corporation Projection system having image oscillation
US5490009A (en) 1994-10-31 1996-02-06 Texas Instruments Incorporated Enhanced resolution for digital micro-mirror displays
US5557353A (en) 1994-04-22 1996-09-17 Stahl; Thomas D. Pixel compensated electro-optical display system
US5689283A (en) 1993-01-07 1997-11-18 Sony Corporation Display for mosaic pattern of pixel information with optical pixel shift for high resolution
US5751379A (en) 1995-10-06 1998-05-12 Texas Instruments Incorporated Method to reduce perceptual contouring in display systems
JPH10268251A (en) 1997-03-27 1998-10-09 Advanced Display:Kk Control method for liquid crystal display device
US5842762A (en) 1996-03-09 1998-12-01 U.S. Philips Corporation Interlaced image projection apparatus
US5897191A (en) 1996-07-16 1999-04-27 U.S. Philips Corporation Color interlaced image projection apparatus
US5912773A (en) 1997-03-21 1999-06-15 Texas Instruments Incorporated Apparatus for spatial light modulator registration and retention
JPH11174489A (en) 1997-12-17 1999-07-02 Matsushita Electric Ind Co Ltd Liquid crystal display device
US5920365A (en) 1994-09-01 1999-07-06 Touch Display Systems Ab Display device
US6028656A (en) * 1996-10-09 2000-02-22 Cambridge Research & Instrumentation Inc. Optical polarization switch and method of using same
EP1001306A2 (en) 1998-11-12 2000-05-17 Olympus Optical Co., Ltd. Image display apparatus
US20020149725A1 (en) 2000-12-25 2002-10-17 Kiyokazu Hashimoto Optical compensatory sheet comprising optically uniaxial or biaxial transparent stretched film
US20040036821A1 (en) * 2002-08-22 2004-02-26 Optiva, Inc. Liquid crystal shutter
CN1550840A (en) 2003-05-09 2004-12-01 精工爱普生株式会社 Viewing angle control element, display device, and electronic apparatus
KR20050058901A (en) 2003-12-13 2005-06-17 엘지.필립스 엘시디 주식회사 Transreflective type liquid crystal display device
JP2005257756A (en) 2004-03-09 2005-09-22 Optrex Corp Display apparatus
US20050254113A1 (en) * 2002-07-08 2005-11-17 Koninklijke Philips Electronics N.C. Reflective stereoscopic display
US20060044495A1 (en) 2004-08-26 2006-03-02 Fuji Photo Film Co., Ltd. Transmissive color liquid crystal display device
JP2006064907A (en) 2004-08-26 2006-03-09 Fuji Photo Film Co Ltd Transmissive color liquid crystal display device
WO2006038574A1 (en) 2004-10-04 2006-04-13 Sharp Kabushiki Kaisha Display and electronic device
US7068336B2 (en) * 2002-12-13 2006-06-27 Lg.Philips Lcd Co., Ltd. Liquid crystal display device having variable viewing angle
JP2006171333A (en) 2004-12-15 2006-06-29 Toshiba Electronic Engineering Corp Liquid crystal display device
JP2006195388A (en) 2005-01-17 2006-07-27 Asahi Glass Co Ltd View-angle control display device and view-angle control element
JP2006330164A (en) 2005-05-24 2006-12-07 Casio Comput Co Ltd Liquid crystal display device
JP2007148278A (en) 2005-10-31 2007-06-14 Optrex Corp Display apparatus
US7468770B2 (en) * 2004-02-26 2008-12-23 Seiko Epson Corporation Viewing angle control element, method of manufacturing the same, liquid crystal display device, and electronic apparatus
US7705933B2 (en) * 2005-01-19 2010-04-27 Seiko Epson Corporation Liquid crystal display apparatus and electronic apparatus
US7742124B2 (en) * 2001-04-20 2010-06-22 Puredepth Limited Optical retarder
US7760292B2 (en) * 2005-10-13 2010-07-20 Lg. Display Co., Ltd. Liquid crystal display device to control viewing angle
US7948580B2 (en) * 2006-05-31 2011-05-24 Sharp Kabushiki Kaisha Liquid crystal display
US7956940B2 (en) * 2006-05-31 2011-06-07 Sharp Kabushiki Kaisha Display system

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4276778B2 (en) * 2000-12-25 2009-06-10 富士フイルム株式会社 Optical compensation sheet manufacturing method

Patent Citations (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4373784A (en) 1979-04-27 1983-02-15 Sharp Kabushiki Kaisha Electrode structure on a matrix type liquid crystal panel
US5061049A (en) 1984-08-31 1991-10-29 Texas Instruments Incorporated Spatial light modulator and method
US4662746A (en) 1985-10-30 1987-05-05 Texas Instruments Incorporated Spatial light modulator and method
US4811003A (en) 1987-10-23 1989-03-07 Rockwell International Corporation Alternating parallelogram display elements
US4956619A (en) 1988-02-19 1990-09-11 Texas Instruments Incorporated Spatial light modulator
US5386253A (en) 1990-04-09 1995-01-31 Rank Brimar Limited Projection video display systems
US5083857A (en) 1990-06-29 1992-01-28 Texas Instruments Incorporated Multi-level deformable mirror device
US5146356A (en) 1991-02-04 1992-09-08 North American Philips Corporation Active matrix electro-optic display device with close-packed arrangement of diamond-like shaped
US5317409A (en) 1991-12-03 1994-05-31 North American Philips Corporation Projection television with LCD panel adaptation to reduce moire fringes
US5309241A (en) 1992-01-24 1994-05-03 Loral Fairchild Corp. System and method for using an anamorphic fiber optic taper to extend the application of solid-state image sensors
US5689283A (en) 1993-01-07 1997-11-18 Sony Corporation Display for mosaic pattern of pixel information with optical pixel shift for high resolution
US5402184A (en) 1993-03-02 1995-03-28 North American Philips Corporation Projection system having image oscillation
US5557353A (en) 1994-04-22 1996-09-17 Stahl; Thomas D. Pixel compensated electro-optical display system
US5920365A (en) 1994-09-01 1999-07-06 Touch Display Systems Ab Display device
US5490009A (en) 1994-10-31 1996-02-06 Texas Instruments Incorporated Enhanced resolution for digital micro-mirror displays
US5751379A (en) 1995-10-06 1998-05-12 Texas Instruments Incorporated Method to reduce perceptual contouring in display systems
US5842762A (en) 1996-03-09 1998-12-01 U.S. Philips Corporation Interlaced image projection apparatus
US5897191A (en) 1996-07-16 1999-04-27 U.S. Philips Corporation Color interlaced image projection apparatus
US6028656A (en) * 1996-10-09 2000-02-22 Cambridge Research & Instrumentation Inc. Optical polarization switch and method of using same
US5912773A (en) 1997-03-21 1999-06-15 Texas Instruments Incorporated Apparatus for spatial light modulator registration and retention
JPH10268251A (en) 1997-03-27 1998-10-09 Advanced Display:Kk Control method for liquid crystal display device
JPH11174489A (en) 1997-12-17 1999-07-02 Matsushita Electric Ind Co Ltd Liquid crystal display device
EP1001306A2 (en) 1998-11-12 2000-05-17 Olympus Optical Co., Ltd. Image display apparatus
US20020149725A1 (en) 2000-12-25 2002-10-17 Kiyokazu Hashimoto Optical compensatory sheet comprising optically uniaxial or biaxial transparent stretched film
US6657690B2 (en) 2000-12-25 2003-12-02 Fuji Photo Film Co., Ltd. Optical compensatory sheet comprising optically uniaxial or biaxial transparent stretched film
US7742124B2 (en) * 2001-04-20 2010-06-22 Puredepth Limited Optical retarder
US20050254113A1 (en) * 2002-07-08 2005-11-17 Koninklijke Philips Electronics N.C. Reflective stereoscopic display
US20040036821A1 (en) * 2002-08-22 2004-02-26 Optiva, Inc. Liquid crystal shutter
US7068336B2 (en) * 2002-12-13 2006-06-27 Lg.Philips Lcd Co., Ltd. Liquid crystal display device having variable viewing angle
CN1550840A (en) 2003-05-09 2004-12-01 精工爱普生株式会社 Viewing angle control element, display device, and electronic apparatus
US20040252258A1 (en) 2003-05-09 2004-12-16 Seiko Epson Corporation Viewing angle control element, display device, and electronic apparatus
KR20050058901A (en) 2003-12-13 2005-06-17 엘지.필립스 엘시디 주식회사 Transreflective type liquid crystal display device
US7468770B2 (en) * 2004-02-26 2008-12-23 Seiko Epson Corporation Viewing angle control element, method of manufacturing the same, liquid crystal display device, and electronic apparatus
JP2005257756A (en) 2004-03-09 2005-09-22 Optrex Corp Display apparatus
JP2006064907A (en) 2004-08-26 2006-03-09 Fuji Photo Film Co Ltd Transmissive color liquid crystal display device
US20060044495A1 (en) 2004-08-26 2006-03-02 Fuji Photo Film Co., Ltd. Transmissive color liquid crystal display device
WO2006038574A1 (en) 2004-10-04 2006-04-13 Sharp Kabushiki Kaisha Display and electronic device
US20080084471A1 (en) 2004-10-04 2008-04-10 Sharp Kabushiki Kaisha Display Device and Electronic Apparatus
JP2006171333A (en) 2004-12-15 2006-06-29 Toshiba Electronic Engineering Corp Liquid crystal display device
JP2006195388A (en) 2005-01-17 2006-07-27 Asahi Glass Co Ltd View-angle control display device and view-angle control element
US7705933B2 (en) * 2005-01-19 2010-04-27 Seiko Epson Corporation Liquid crystal display apparatus and electronic apparatus
JP2006330164A (en) 2005-05-24 2006-12-07 Casio Comput Co Ltd Liquid crystal display device
US7760292B2 (en) * 2005-10-13 2010-07-20 Lg. Display Co., Ltd. Liquid crystal display device to control viewing angle
JP2007148278A (en) 2005-10-31 2007-06-14 Optrex Corp Display apparatus
US7948580B2 (en) * 2006-05-31 2011-05-24 Sharp Kabushiki Kaisha Liquid crystal display
US7956940B2 (en) * 2006-05-31 2011-06-07 Sharp Kabushiki Kaisha Display system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
International Search Report for PCT/JP2007/058252, mailed Jul. 3, 2007.
Supplementary EP Search Report mailed Aug. 19, 2010 in corresponding EP application 07741688.1.

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100060824A1 (en) * 2007-01-31 2010-03-11 Takehiko Sakai Viewing angle controlling liquid crystal panel and display device
US8169567B2 (en) * 2007-01-31 2012-05-01 Sharp Kabushiki Kaisha Viewing angle controlling liquid crystal panel and display device
US20090317773A1 (en) * 2008-06-24 2009-12-24 United States Of America As Represented By The Administrator Of The N.A.S.A. Variably Transmittive, Electronically-Controlled Eyewear
US8411214B2 (en) * 2008-06-24 2013-04-02 United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Variably transmittive, electronically-controlled eyewear
US20120044430A1 (en) * 2010-08-18 2012-02-23 Chunghwa Picture Tubes, Ltd. 3D Image Display Device
US20180143468A1 (en) * 2015-05-27 2018-05-24 Panasonic Intellectual Property Management Co., Ltd. Optical device

Also Published As

Publication number Publication date
HK1128966A1 (en) 2009-11-13
JPWO2008018212A1 (en) 2009-12-24
US20090174843A1 (en) 2009-07-09
KR20090017499A (en) 2009-02-18
EP2051134A4 (en) 2010-09-22
WO2008018212A1 (en) 2008-02-14
EP2051134A1 (en) 2009-04-22
JP5037508B2 (en) 2012-09-26
CN101427177A (en) 2009-05-06
CN101427177B (en) 2010-12-29

Similar Documents

Publication Publication Date Title
US8045097B2 (en) Liquid crystal display device and viewing angle control module
JP4819122B2 (en) Liquid crystal display device and viewing angle control panel
EP1475655B1 (en) Viewing angle control element, display device, and electronic apparatus
US7728932B2 (en) Liquid crystal display device with particular phase plates having specific axis angles
US8736796B2 (en) Liquid crystal panel and liquid crystal display device
US7932975B2 (en) Liquid crystal display device
US20090096954A1 (en) Liquid crystal display
US20080123025A1 (en) Liquid crystal display device with two liquid crystal
JP2009020293A (en) Display and viewing angle control device used for the same
JP2008096458A (en) Display and viewing angle controller to be used for the same
JP2008310271A (en) Liquid crystal display device and viewing angle control panel
US8189147B2 (en) Liquid crystal display device
JPWO2019103012A1 (en) Display device
JP2005352474A (en) Color display device
JP2005292709A (en) Liquid crystal display element
JP2006039369A (en) Transflective liquid crystal display device and electronic equipment mounted with the same
JP2008064790A (en) Display, and viewing angle controller used therefor
JP2005084593A (en) Liquid crystal display element and method for manufacturing the same
JP2008299280A (en) Display and viewing angle controller used for the same
WO2007094358A1 (en) Display, and viewing angle control device used therein
JP4686164B2 (en) Liquid crystal display
JP2007072148A (en) Liquid crystal apparatus and electronic equipment
JP2008165043A (en) Liquid crystal display element
JP2008051993A (en) Electro-optical device, viewing angle control element, and electronic apparatus
JP2006053498A (en) Color display device

Legal Events

Date Code Title Description
AS Assignment

Owner name: SHARP KABUSHIKI KAISHA, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SAKAI, TAKEHIKO;OKAZAKI, TSUYOSHI;MORISHITA, KATSUHIKO;AND OTHERS;REEL/FRAME:021713/0321;SIGNING DATES FROM 20080926 TO 20080930

Owner name: SHARP KABUSHIKI KAISHA, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SAKAI, TAKEHIKO;OKAZAKI, TSUYOSHI;MORISHITA, KATSUHIKO;AND OTHERS;SIGNING DATES FROM 20080926 TO 20080930;REEL/FRAME:021713/0321

ZAAA Notice of allowance and fees due

Free format text: ORIGINAL CODE: NOA

ZAAB Notice of allowance mailed

Free format text: ORIGINAL CODE: MN/=.

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8

FEPP Fee payment procedure

Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

LAPS Lapse for failure to pay maintenance fees

Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20231025